Cooking in biblical times commonly involved roasting or boiling meat. Animals such as kids, lambs, and calves were prepared for hospitality and festivity, while boiling was the more usual method of cooking.
The Passover animal was preserved whole and roasted over a fire. Meat could also be boiled after the animal was slaughtered and prepared. The blood was poured out before the meat was cooked.
Meat was not an ordinary part of the Jewish diet, so the art of cooking was not developed to the same extent as in cultures where meat was more common. Roasting could be done over a fire or perhaps in a simple earth oven.